Abstract: Supercooling of the microencapsulated phase change materials(PCMs) during cooling usually happens. This phenomenon can interfere with heat transfer and is necessary to further overcome. In this study, melamine- formaldehyde microcapsules containing two n-alkane PCMs, namely, n-dodecane(C₁₂) or n-tetradecane(C₁₄) were prepared by in situ polymerization. A small amount of n-hexatriacontane(C₃₆) was introduced as an organic gelator into the core of microcapsules to cope with the supercooling problem. Analyses demonstrate that supercooling of the microencapsulated C₁₂ or C₁₄ was significantly suppressed by adding 3%(mass fraction) C₃₆, without changing the spherical morphology and dispersibility. It could be also found that the enthalpy of microencapsulated C₁₂ or C₁₄ containing C₃₆ was similar to that of microencapsulated n-alkanes without C₃₆, whereas the difference between onsets of crystallization and melting(degree of supercooling) is similar to that of those of pure n-alkanes, suggesting the remarkable suppression ability of the organic gelator on supercooling.

Key words: Supercooling, Microcapsule, Phase change material, Gelator, n-Alkane